The Killer Santa was an unnamed criminal who on Christmas Eve 1971, went into a general store to rob it, using a Santa Claus suit as a disguise. He shot and killed the store's clerk Mr. Levitt after he tried to draw his gun. He then quickly fled the store with being able to steal only $31.

After he fled the general store, the Chapman family was heading home after seeing Grandpa Chapman at a mental facility. The family had the unfortunate chance to run into the man. The family noticed him flailing his arms to get their attention and it appears his car was broken down on the road.

Billy, scared because of the story his grandfather had told him about Santa, pleaded for his father not to stop for him, but his father pulled over anyway. The killer Santa walked up to the car and Jim asked the man if he need a ride and he replied he did not and that he was low on luck and immediately pulled out his hand gun, intending to steal the family's sports wagon. Billy's mother freaks out and screams for Jim to escape as Billy quickly gets down. Jim immediately tried to drive in reverse and escape the man, but the man unfortunately managed to shoot and kill Jim, making the car fall in a ditch on the side of the road.

Ricky immediately starts crying. Quickly, Billy got out of the car and ran into nearby bushes to hide. The killer Santa opened the door, letting Jim's body fall out onto the road. The killer Santa then pulled Ellie out of the car and pinned her to the ground, intending to rape her as he rips her blouse open. Ellie hit him across the face, making him change his mind and hit her back. He then brought out a switchblade and slit her throat. After this, he tried to search for Billy, but changed his mind and quickly fled the scene, leaving Billy and Ricky alive.

It is unknown what happened to him after the killings. It is likely that he was eventually caught and arrested for his crimes.

The Killer Santa would leave a huge impact on Billy and Ricky and make them have insanity and become killer Santa Claus themselves.

The Killer Santa makes a strange cameo in Silent Night, Deadly Night Part 2 through archive footage. When Ricky goes to the cinema to see a movie with Jennifer, he discovers the movie is about a man going around killing people dressed like Santa. The film is then shown to actually be Silent Night, Deadly Night, depicting the Killer Santa shooting the clerk and running away with the money.

There are some viewers who theorize that The Killer Santa is actually a younger Charles Lee Ray from the Child’s Play franchise, which would mean that the two films exist in the same universe.